A STUDY OF THE EXPANSION CHARACTERISTICS OF AN ORDINARY PORTLAND CEMENT WITH A HIGH AUTOCLAVE EXPANSION

A STUDY WAS MADE OF THE EXPANSION CHARACTERISTICS OF HARDENED PASTES OF AN ORDINARY PORTLAND CEMENT WITH A HIGH AUTOCLAVE EXPANSION. THE BEHAVIOUR OF MORTAR MADE WITH THIS CEMENT WAS ALSO INVESTIGATED. SPECIMENS WERE EXAMINED FOR EXPANSION DURING MOIST CURING, AT 22 DEGREES, DURING IMMERSION IN BOILING WATER, DURING AUTOCLAVING AND WHILE THEY WERE BEING SUBJECTED TO COMBINATIONS OF THESE TREATMENTS. THE FOLLOWING ASPECTS ARE PRESENTED AND DISCUSSED: (1) THE INFLUENCE OF CURING OF PASTES AT A RELATIVE HUMIDITY OF 95 PER CENT, AT 22 DEGREES, ON THE EXPANSION IN THE AUTOCLAVE AND DURING IMMERSION IN BOILING WATER, (2) THE INFLUENCE OF AUTOCLAVE PRESSURE AND OF AUTOCLAVING TIME ON EXPANSION DURING AUTOCLAVING, (3) THE INFLUENCE OF IMMERSION IN BOILING WATER ON AUTOCLAVE EXPANSION, AND (4) DIMENSIONAL CHANGE DURING REPEATED CYCLES OF WETTING AND DRYING. FOR PURPOSES OF COMPARISON TESTS WERE ALSO CARRIED OUT ON A PORTLAND CEMENT WITH A LOW AUTOCLAVE EXPANSION. IT WAS FOUND THAT THE AUTOCLAVE EXPANSION AND THE EXPANSION DURING IMMERSION IN BOILING WATER OF THE CEMENT WITH A HIGH AUTOCLAVE EXPANSION ARE INFLUENCED BY THE PRE-CURING. THE EXPANSION DURING IMMERSION IN BOILING WATER INCREASED WITH INCREASED PRE-CURING TIMER. PRE-CURING WAS CARRIED OUT AT 22 DEGREES AND A RELATIVE HUMIDITY OF 95 PER CENT AND MAXIMUM EXPANSION OF THE CEMENT OCCURRED AT BETWEEN 8 AND 16 DAYS OF THE PRE- CURING PERIOD, AFTER WHICH THERE WAS A GRADUAL DECREASE IN EXPANSION. THE AUTOCLAVE EXPANSION DECREASED WITH INCREASED PRE-CURING TIME. /RRL/A/

• Supplemental Notes:
  • No 251, 8 PP, 14 FIG, 1 TAB, 3 PHOT, 11 REF
• Authors:
  • Van Rensburg, J J
  • Kruger, J E
  • Van Aardt, J H
• Publication Date: 1967

Media Info

• Serial:
  • Csir Research Reports /South Africa/

Subject/Index Terms

• TRT Terms: Alternatives analysis; Autoclave curing; Concrete curing; Expansion; Humidity; Mortar; Pastes; Portland cement; Wetting and drying tests
• Uncontrolled Terms: Autoclaves; Immersion
• Old TRIS Terms: Autoclaving
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00212809
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Mar 18 1994 12:00AM